Drought tolerance of faba bean (Vicia faba L.) can be improved by specific LED light wavelengths

Abstract

A light wavelength affects both plant photomorphogenesis and stress resistance. In this study, the phenotypic plasticity (growth parameters and cuticular waxes) and physiological adaptation (photosynthetic properties and antioxidant enzyme activities) of faba bean subjected to specific LED lights, red, yellow, blue, violet, and white, were analyzed under two water conditions (normal and drought). The plants grown under red and yellow lights possessed the smaller leaf size and the higher leaf relative water content. The blue light had a positive effect on improving stomatal conductance and net photosynthetic rate of faba bean leaves, and the plants grown under the blue light also had higher antioxidant enzyme activities. The blue light also changed the dominant wax component to alkanes and significantly decreased a total wax load under the drought stress, and thus minimized the cuticle transpiration (water loss). The decreased wax deposition and the increase of C31-C33 alkanes abundance in plants grown under the yellow light also resulted in a lower leaf water loss under the drought stress. The red light increased but the violet light did not change the cuticle water loss. These results suggest that plant drought tolerance could be improved by supplementing the blue and yellow lights.

Keywords

• cuticle resistance
• morphological adaptation
• physiological responses
• wax chemical profile